1. Field of the Invention
The present invention relates to a method of printing using an ink jet printer, and more particularly, to a method of separating raster data for printing using an ink jet printer.
2. Description of the Prior Art
Ink jet printers typically include a printhead which is carried by a carriage assembly which is moved in transverse directions across the print medium, relative to the advance direction of the print medium within the printer. For a mono-color printhead used to jet a single color ink onto the print medium, the printhead is scanned across the print medium in one transverse direction, advanced a distance corresponding to the height of the printhead, and scanned in a return direction back across the print medium in an opposite direction. Ink is jetted from the ink emitting orifices in the printhead as the printhead scans in the transverse directions across the print medium. An image area is defined via software which overlies the print medium. The image area includes a plurality of rows of pixel locations and a plurality of columns of pixel locations. As each ink emitting orifice is scanned across an associated pixel location on the image area, a determination is made as to whether ink is to be jetted from the associated ink emitting orifice onto the print medium at the selected pixel location. By sequentially scanning the printhead across the print medium and advancing the print medium during scans a distance corresponding to the height of the printhead, ink may be selectively jetted onto the print medium at any pixel location within the image area.
For multiple pass printing, full swaths of data to be printed are calculated and then the dots that are not to be printed are zeroed out. The disadvantages to this are that processing time and bandwidth are wasted by formatting bits that will later be zeroed out. For example, if 50% of the dots are known to be zero, the bus bandwidth is 50% greater than needed and more memory will have to be used to store the swath.